Perfluoroalkylene ether and thioether triazine compounds

ABSTRACT

The invention provides triazines of the formula   D R A W I N G

United States Patent [72] Inventors George A. Grindahl;

Ogen R. Pierce; John R. Greenwald, Midland, Mich.

[21] Appl. No. 771,291

[22] Filed Oct. 28, 1968 [45] Patented Mar. 2, 1971 [73] Assignee DowCorning Corporation Midland, Mich.

[5 4] PERFLUOROALKYLENE ETHER AND THIOETHER TRIAZINE COMPOUNDS 7 Claims,No Drawings [52] U.S. Cl. 260/248, 260/78.4, 260/564 [51] Int. Cl C07d55/50 [50] Field of Search .1. 260/248 (CS) (Chemical Abstracts1907-June 1969) [56] References Cited UNITED STATES PATENTS 3,317,4845/1967 Fritz et a1 260/248X 3,453,275 260/248 7/1969 Grindahl et al.

Primary Examiner-John M. Ford Attorneys- Robert F. Fleming, Jr, LaurenceR. Hobey and Harry D. Dingman ABSTRACT: The invention provides triazinesof the formula elastomers.

PERFLUOROALKYLENE ETHER AND THIOETHER TRIAZINE COMPOUNDS This inventionrelates to novel triazines. In one aspect the invention relates topolymeric fluorine-containing triazines, which have utility as thermallyand oxidatively stable elastomer ingredients, sealants, resins, oils andcoatings. These polymeric triazines. also exhibit a high degree ofsolvent resistance and retain their properties at low temperatures.

Polymeric triazines are known in the prior art. More particularly, U.S.Pat. No. 3,317,484 discloses three-dimensional polymers havingperfluoroether linkages from each carbon atom in the triazine ring.These polymers are obtained by the trimerization of three dinitriles toform the ring. The present invention provides a linear triazine polymerwhich contains only one perfluoroether or thioether linkage betweentriazine rings.

It is an object of the invention to provide linear triazine polymerscontaining ether or thioether linkage.

Another object of the invention is to provide an elastomeric polymerwhich is thermally stable.

These and other objects will be apparent to one skilled in the art uponconsideration of the following specification and appended claims.

According to the invention, there are provided triazine compounds of theformula where Y is a perfluoroalkylene radical containing at least oneether or thioether linkage.

R, is a monovalent polyfluorinated hydrocarbon radical of no more than12 carbon atoms, and X is bromine or iodine.

Rf can be any suitable monovalent fluorhydrocarbon radi' cal, such as,perfluoroalkyl, for example, trifluoromethyl, iso(heptafluoropropyl),perfluoroisobutyl, perfluorooctyl or perfluorodecyl; unsaturatedfluorocarbon radicals, for example, pentafluorallyl and4-perfluorohexenyl; perfluorocycloaliphatic radicals such asperfluorocyclohexyl, perfluorocyclopentyl; or any aryl-containingradical, for example, pentafluorophenyl, nonafluoroxenyl,heptafluorotolyl, heptafluoronaphthyl, heptafluorobenzyl orB-perfluoro/3-phenylethyl. Also included are monovalent hydrocarbonradicals partially substituted with fluorine such a trifluoroethyl and3,3,3,-trifluoropropyl.

R, is preferably trifluoromethyl, trifluoroethyl or other fluoroalkylradical. The presence of small amounts of fluoroolefinic radicalsprovides crosslinking sites in polymers of the above-describedtriazines.

As described above, Y is a perfluoroalkylene radical containing at leastone ether or thioether linkage. Representative of ether linkages arecompounds of the general formulas E K? mC FzOLfFCEN where n is aninteger of from O to 12,

NECCFO(CF2)mOCFCEN where m is an integer of from 2 to 12,

where y is an integer of from to 100 and n is as defined above,

where m is an integer of from 2 to 12, and u w is an integer of O to100. In each of the above structural formulas Z is fluorine or a CRradical.

Representative of the perfluoroalkylene radicals containing at least onethioether linkage are compounds having the general structures (-CF S(-CFwhere a is an integer of from 1 to 3 and (-CF -),,S(-CF -),,S(-CF wherea is an integer of 1 to 3 and b is an integer of from 2 to 6.

The two X groups in the above-defined triazine provide coupling sitesfor the synthesis of polymers, thus the compounds have particularutility as precursors for linear triazine polymers.

Further in accordance with the invention, there are provided linearpolymeric triazine compounds consisting essentially of units of theformula R; and Y are as defined above.

The triazine compounds (I) can be prepared by two methods. In the firstmethod, the addition of excess ammonia to perfiuoroetherorperfluorothioether-dinitriles results in the formulation of a diamidinecompound. After removal of excess ammonia, the addition of bromooriododifluoroacetonitrile thereof forms a diimidoylamidine. Acylation andcyclodehydration of the diimidoylamidine by reaction with a fluorinatedacid anhydride gives the triazine com pound (I) of the invention. Thereaction sequence is as follows:

The dinitrile starting materials can be synthesized from perfluorooxaand thiaglutaric acids. Also suitable perfluoroether-dinitriles and amethod for their preparation are disclosed in U.S. Pat. No. 3,317,484.

In the second method, bromoor iododifluoroacetonitrile is reacted withammonia to form an amidine which in turn is reacted with apolyfluorinated nitrile to form an imidoylamidine. Addition of a diacidchloride containing the perfluoroalkylene radical having ether orthioether linkages acylates the imidoylamidines to give a product, whichwhen treated with an acid anhydride or excess diacid chloridecyclodehydrates to give the triazine compound (I). The reactions are asfollows:

The bromodifluoroacetonitriles are known in the art and methods of theirpreparation involve known processes. Iododifluoroacetonitrile andhomologues thereof can be prepared in accordance with U.S. applicationSer. No. 467,1 l0, filed Jun. 25 1965, by William X. Bajzer, nowabandoned.

The linear triazine polymers (11) are produced by condensing thetriazine monomer (I). This condensation is effected by heating thedefined triazine monomers to a temperature of at least 30 C. in thepresence of mercury. The temperature at which the condensation takesplace varies depending on the reaction conditions. When ultravioletlight is employed, the reaction occurs at 30 C. or above, preferably 50C. or above. When heat alone is used, the reaction goes best at 150 C.or above. Of course, the reaction temperature should be below thedecomposition temperature of the triazine. In the absence of ultravioletlight the reaction temperature is generally 200 to 300 C. This processcan be performed at any suitable pressure and is preferably carried outin an inert atmosphere.

The following examples are illustrative of the invention which isproperly delineated in the appended claims.

EXAMPLE 1 Approximately 500 milliliters of anhydrous ammonia werecondensed in a cooled flask. While maintaining the ammonia at 70 C.,51.8 grams (0.097 mole) of a mixture of isomeric dinitriles (C F O Nwere added dropwise over a l-hour period. Cooling was stopped and theammonia allowed to evaporate. Residual ammonia was removed by evacuatingthe flask for 1 hour. The product was a mixture of and Dry methylenechloride (400 milliliters) was added to the mixture, the slurry wascooled to C., and 50 grams of bromodifluoroacetonitrile were added toproduce a mixture of diimidoylamidines. After stirring overnight, 105grams (0.5 mole) of trifluoroacetic anhydride were slowly added.Reaction of the diimidoylamides with the acid anhydride produced amixture of the following triazines The mixture was washed 3 times withone-liter portions of water and then dried. Evaporation of the methylenechloride gave grams of oil which showed triazine absorption in theinfrared region.

EXAMPLE 2 64.7 grams of the triazine monomer mixture obtained in example1 and 437 grams of mercury were heated for 3 days at 230 C. At the endof this time, 70 grams of crude polymer, a yellow rubbery material, wereobtained. The polymer was heated under vacuum to remove the mercuryresidue. The purified product was a polymer containing Analysis was asfollows: Calculated for (-C, F N O C, I

26.0; F, 60.75; N. 9.6. Found: C, 25.7; F, 65.7; N, 8.80.

parts of the polymer were milled with 5 parts of tetraphenyl tin(crosslinking agent). The sample was vulcanized in a press for 16 hoursat 160 C. The properties of the vulcanized polymer are given below:

Stress (psi) 10 2125 29 39 48 58* Strain (percent) 20 40 50 60 80 100sample failed This example demonstrates the preparation of theelastomeric triazine polymers of the invention.

EXAMPLE 3 200 milliliters of ammonia were condensed in a flask andallowed to warm to reflux. Bromodifluoroacetonitrile (88 grams) wasevaporated into the flask. Excess ammonia was removed under vacuum.After removal of the ammonia, 200 milliliters of methylene chloride wereadded and this slurry was stirred while 21.7 grams ofB-oxaperfluoroglutaronitrile in 100 milliliters of methylene chloridewere rapidly added. The addition was accomplished in 5 minutes. Somewarming was evident; the mixture was intermittently cooled to maintainthe reaction mixture at about 25 C. A solution of 430 grams oftrifluoroacetic anhydride 200 milliliters of methylene chloride whichhad been cooled to a l0" C. was added to the This mixture was stirredfor one-half hour and then poured into 2 liters of water at 0 C.

| l CF;

having a boiling point of 9397 C./ l mmJ-lg. and an u of- 1.4175. Theinfrared spectrum showed the characteristic triazine adsorption.

EXAMPLE4 Thionyl chloride, 100 milliliters (162 grams) was cooled 109 C.and treated with 61.4 grams (O,276-mole) of B-thiaperfluoroglutaricacid, in small increments. There was no ex otherrnic reaction so thetemperature was-increased to C'. for 20hours. Wet pyridine, 0.05milliliters, was added and the reaction mixture was heated slowly toreflux and kept there for 6 hours. Fractionation of theproduct mixturegave unreacted thionyl chloride and 63.9 grams of B-thiaperfluoroglutaryl chloride, having a boiling point of 57.558.5 C. at mm./Hg.

Analysis: calculated for C Cl F 0 S:' %C., 18.55; %F., 29.34; %Cl,27.38;'Found: %C., 18.8; %F;, 30.1; %CI, 26.9.

Bromodifluoroacetamidine, 1.24 moles, was prepared by adding 194 grams(1.24 moles) of bromodifluoroacetonitrile to an excess of liquid Nl-l at65 C. and then removing the excess of NH by evaporation until a white.free-flowing powder resulted. This solid was suspended in 500milliliters of dry CH C1 at-75 C. and treated with 165grams of CF5CNover the'temperature range 75? to +25 C. Thesolution ofbromodifluoroacetimidoyl-N-trifluoroacetamidine was'cooled to 5 C. andtreated with-59.8 grams (0.24 mole) of B-thiapen fluoroglutaryl chloridedropwise over a period of 1 hour. An additional milliliters of dry CH CIwas added to facilitate stirring. The pastymixture'was then treated with440 grams (2.1 moles) of trifluoroacetic anhydride to effectcyclodehydration. After a brief period of-refluxing to ensure completering closure, the solution wascooled and poured onto ice. The organicphase plus CH CI extracts of the aqueous phase were combined, dried, andfractionatedi to yield 50.0 grams of a,w-di-(4-bromodifluoromethyl-6trifluoromethyl-s-triazinyl)-B-thiaperfluoropropane having a boilingpoint of 75 76 C./0. 15 mm. Hg.

Analysis: calculated for CIZFHBQSNGZ %C., 21.01; Found: %C., 20.95. Fn.m.r. spectroscopy (CFCl reference) shows three singlets at 59.9 ppm.(CF Br, 2.0), 72.2 p.p.m: (CF 3.1),

75.5 ppm. C-CF -S-, 2.0) in agreement with the proposed structure.Infrared spectroscopy reveals the typical triazine absorption at 6.46;!

vacuum to sublime mercury and mercury salts. The product was a linearpolymer ofthe following units:

The brown, tack-free polymer was-elastomeric at room -tem-.

peraturebut brittle at 20C. When heated in'nitrogen at a...

where R, is a monovalent. polyfluorinated hydrocarbon radical containingfrom 1 to.12 inclusive carbonatoms;

X'is a bromine or iodine atom; 5121 Y is a perfluoroalkylene radicalcontaining-at leastlonez ether orthioether. linkage selected from thegroup conwhere mis an integer of from 2 to 12;

0 0 Fz),.OF20(c|1FCF20) (|3FC Z z.

where y is an integer of from 0 to and n is an integer of.

where m is an integer of from 2 to 12, u w is an integer offr'om-O to100, Z being fluorine orv a CR, radical; ('-CF -)aS(- CF' where a is aninteger of from 1 to 3; and (-CF -),,S(--

CF -),,S(-CF whereu-is an integer of from 1 to 3 and-b is an,.

integer of from 2 to 6'.

2. A compound of claim- 1*where Y is a perfluoroalkylene.

radical containing atleast one ether linkage selectedfrom the.

group consistingof C(C F9110 F 0OFOwhere n is an integer of from 01:012;

-G C F O (C FQmO C FC-where m is an integer of from 2'to 12;

C(CF2),,CF2O(CFOFzO) CFCwhere y is an integer of from 0 to 100 and nlsan integer of from 0 to 12; and

integer of from 2 to 12, u +-w is anintegerof'from 0 to 100', Z.beingfluorine or'a CF; radical.

3. A compound of claim 2.where Y is a 4. A compound of claim 2 where Yis a -CF --CF radical. 5. A compound of claim 2 where Y is a radical.

2. A compound of claim 1 where Y is a perfluoroalkylene radicalcontaining at least one ether linkage selected from the group consistingof
 3. A compound of claim 2 where Y is a radical.
 4. A compound of claim2 where Y is a -CF2-0-CF2radical.
 5. A compound of claim 2 where Y is aradical.
 6. A compound of claim 1 where Y is a perfluoroalkylene radicalcontaining at least one thioether linkage selected from the groupconsisting of (-CF2-)aS(-CF-)a where a is an integer of from 1 to 3 ;and (-CF2-)aS-(CF2-)bS(-CF2-)a where a is an integer of from 1 to 3 andb is an integer of from 2 to
 6. 7. A compound of claim 6 where Y is a-CF2-S-CF2- radical.